This invention relates to metal plating and, more particularly, to fabrication procedures for preparing plated target anodes for X-ray generators.
X-ray generators are utilized in a variety of applications of practical importance. One significant area in which such sources are employed is the field of X-ray lithography. An advantageous X-ray lithographic system utilized to make structures such as large-scale-integrated (LSI) semiconductor devices is described in IEEE Transactions on Electron Devices, Vol. ED-22, No. 7, July 1975, pages 429-433. In an attempt to increase the throughput of such an X-ray lithographic system, efforts have been directed at trying to increase the power output of the X-ray generator included therein.
X-ray generators comprising rotating or stationary plated target anodes are available for use in lithographic systems. However, reliability problems arising from high power operation of such anodes have made generators of the plated type unattractive for many practical lithographic applications. In particular, interdiffusion effects and microcracks due to thermal stresses have limited the high-power reliability of plated anodes as heretofore constructed. Accordingly, efforts by workers in the lithographic field have been directed at trying to devise a reliable high-power X-ray source of the plated anode type characterized by high stability and long lifetime. It was recognized that such a source, if available, could be a basis for a rugged production-type X-ray lithographic system exhibiting advantageous throughput properties.